Field of the Invention
The present invention relates to a quantum cascade laser. This application claims the benefit of priority from Japanese Patent application No. 2015-137922 filed on Jul. 9, 2015, which is herein incorporated by reference in its entirety.
Related Background Art
A semiconductor laser for optical communications is disclosed by the following document: Jpn. J. Appl. Phys., Vol. 39, pp. L1297-1299, 2000, which will be referred to as Non-Patent Literature.